<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<ul id="ul">
    <li>2</li>
    <li>3</li>
    <li>1</li>
    <li>1</li>
</ul>
<script type="text/javascript">
    var ul=document.getElementById('ul');
    var li=ul.getElementsByTagName('li');
    console.log(li);
</script>
</body>
</html>